Digging tooth



L.. s. SHAFFER DmGING lTOOTH Filed Oct. 6, 1928 Huug. 'i

INVENTOR LAYTON SHAFFfR 9W 6( ATTORNEY.;

Dec. 22, 1931,

Patented Dec. 22, .-1931 .UNITED ASTATES PATENT oEFlcE LAYTON S.. SHAFFER, 0F RAVENNA, OHIO, ASSl-[GNOR T0 MACHINE COMPANY, OF RAVENNA., OHIO, A CORPORATION 0F MARYLAND ,DIGGING TOOTH Application led October 6, 1928. Serial' No. 310,775.

The present invention, relating, as indicated, to a digging tooth, is more particularly directed to an improved tylpe of removable and renewable tooth for removable attachc ment to the forward or digging edge of excavating shovels for use in such machines as railroad shovels, outstroke and instroke ditching machines, digging buckets and the like. The principal obJect of the invention is the provision of an improved tooth of the type` referred to in which the separate or removble digging end of the tooth proper is provided with a secure engagement a ainstthe tooth proper on a multiplicity o sides at angles to each other, thus insuring an engagement which will prevent relative movement between point and tooth in any direction. In this way the looseness, which has characterized removable teeth in thepast and the resultant shock loads on the tooth proper are avoided, with the result that a very considerably-increased life is securedin the tooth proper, which in present constructions is subject to frequent breaka e at the point of connection to the removable end lportion.

To the accomplishmentfof the foregoing and related ends, said invention, then, consists of the means' hereinafterfully described .and particularly pointed out in the claims; the annexed drawings and the following description setting forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

4In said annexed drawings Fig. 1 is a side elevation of a digging bucket, the bucket shown merely illustrating one form of such device to which my improved tooth may be applied; Fig. 2 is a longitudinal central section of my improved tooth taken on the line Qf-2 of Fig. 4; Fig. 3 is a section through the tooth and point on the lines 3 3 and 35-3, Fig. 2, respectively; and Fig. 4 is a section on the line 4 4, Fig.'2. v

vIn removable teeth now in common use for excavating buckets, shovels and the like, it is the standard practice to provide a tooth having bifurcated end portions engaging on the upper and lower sides of the digging side of the shovel, the tooth then having a tapered end portion in which the taper or converging surfaces are on the upper and lower sldesf Over this tapered end there is removably engaged a tooth point having corresponding internal converging surfaces which wedge onto the converging surfaces of the tooth proper, the lateral engagement then being veffected by means of a tapered bolt passed 4as the tapered bolt wears and allows the point .'to oscillate slightly from side to side on they tooth.' The resultv is that eventually, and almost invariably before the point is worn out, it is'so loosened on the tooth that it breaks olf 'the vtooth close to the side of the rear edge of the point. When this happens of course the entire tooth has to be replaced, instead of merely the .removable point, at a considerable expense.

The present invention consists in a tooth proper having a bifurcated shank engaging over the digging side of the bucket as inthe ordinary construction and having an end portion-on the sharply converging top and bottom surfaces.l -I have provided, however, a renewable, removable point or tip which engages over the end of the shank with not only a vertical wedging en agement, but with a quadruple vlateral edging engagement which effectively locks the tooth and point against movement in any direction, this engagement being such as to constitut'ein effect an integration of the tooth and point so that shocks on the point are'transmitted directly to the tooth, and as a result of this engagement, the point wears out before the shank breaks.

Referring to the drawings, I have shown in Fig. 1 a bucket 1 open at the forward or digging side 3 andhaving a bottom 4, en

further shown as fixed on the end of what is ordinarily termed a digging stick 6. The tooth 5 is provided with 'a bi urcated shank consisting of an upper short arm 7 and a lower longer arm 8, these arms engaging respectively against the top and bottom sides of the digging side 4 of the shovel, where the tooth is secured by bolts passing through this wall of the shovel or in any other suitable manner. The forward end of the tooth is provided with sharply converging surfaces 9 and 10, each of which is provided with tapered keyways 21 and 22, the walls of these keyways diverging toward the tip or point of the tooth. The lateral outer surfaces of the tooth are also tapered, these surfaces converging toward the tip of the tooth, in this way providing angularlyl related surfaces 11, 12, 13 and 14 on the tooth.

The removable tip of the tooth, which may be formed of some extremely tough, hard material, such as manganese steel, is hollow and is provided with upper and lower internal surfaces 15 and 16 tapered to correspond with the surfaces 9 and 10 on the tooth 5 so that when the tip is slipped over the tooth it will provide a tapered vertical engagement. The tip is also provided with keys 17 and 18 having tapered surfaces 12 and 13', respectively, the angle of the taper corresponding exactly with the angle of taper between the surfaces 12 and 13 in the keyways on the tooth 5. Similarly, the inner side walls 11 and 14 of the tip have tapered surfaces, the taper corresponding with the taper on the surfaces 11 and 14 of thevtip.

This engagement of tapered lateral surfaces allows for four pairs of complementary engaging surfaces, namely, the surfaces 11, 11, 12, 12', 13, 13 and 14, 14. Since both the removable tip and the end of the tooth proper are cast and it is not desired to machine them there will rarely be an exact engagement between all of these complementary surfaces. The great advantage of my construction, however, is that regardless of the inaccuracies and shrinkage in the castings there are so many complementary surfaces that invariably some two of the fou pairs of surfaces will be in engagement and will act to wedge the tip of the tooth. Thus, either the surfaces 11 and 14 will engage with reasonable accuracy against the surfaces 11 and 14 of the tooth, or the surfaces 11 and 12 against the walls 11 and 12, or the sur- Y faces 13 and 14 against the walls 13 and 14, or the walls 12 and 13 against the walls 12 and 13. All of these lateral tapered surfaces are given the same taper, consisting of an angle of only five degrees from the longitudinal central axis of the tip of the tooth and thus, although engagement between the cooperating tapered surfaces 1s edected considerably prior to the engagement between l the upper and lower tapered surfaces 9 and 10, it is still possible to drive the tip home into an engagement with the surfaces 9 and 10 even after the lateral engagement has been effected.

By the above construction it is possible to engage the removable tip very securely on the tooth with an engagement which prevents not only vertical movement between these two parts but also lateral movement. The result of this engagement is to greatly minimize the possibility of breakage of the tooth from lateral shock transmitted through the tip, and in practice it has been found that lateral breakage of the tooth shank approximatelyv opposite the inner end of the tip is almost impossible.

It will be noticed that the transverse surfaces of the keys 17 and 18 do not bottom in contact with the transverse surfaces of the keyways 11 and 12 as it is desired to secure the vertical engagement entirely between the surfaces 9 and 10, and 15 and 16, the keys of the keyways serving merely to provide additional tape-red lateral surfaces to secure effective lateral engagement. After the tip is engaged upon the tooth it may be locked in such position by means of a tapered bolt 2O engaging in the registering tapered openings 23 in the tip and in the tooth 5, and the projecting head of the bolt and also of the nut are protected against injury by suitably shaped guards or projections 24v on the sides of the tip. i

The present invention has several important advantages, both in the manufacture of the tooth and in its use. In manufacturing the present tooth, both the tooth proper and removable point may be east, each of the most desired material, and the engaging surfaces formed on the tooth and point are so related that the point may then be driven on the'tooth into a secure engagement regardless of the slight irregularities in the formation of either element. Such irregularities-are of course to be expected in cast articles and as it is desired to make the tip of extremely tough, hard material, such as alloy steel or hardened steel, it is not desirable nor economical to have to machine any parts of the point. By presenting a multiplicity of angularly related engaging surfaces in a plurality of planes it is possible to secure an extremely rigid engagement between point and tooth. I

From the standpoint of use the present tooth has equally important advantages derived from the secure. engagement of the point on v`the tooth as this eliminates any movement which permits shock.

Other modes of applying the principle of my invention may be employed insteadA of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the followsaid end and havin I therefore particularly point out and dis.-

tinctly claim as my invention :-k

1. A digging tooth comprising a body por-v tion having an' end with sharply convergent y upper and lower surfaces and slightly convergent lateral surfaces, and a removable hollow point adapted tolbe engaged over said endand having internal surfaces arranged and disposed to engage against the respective convergent surfaces on said end to rovide a wedge engagement` therebetween, t e upper and lower surfaces of the end of the body portion having keyways tapering in width.

2. A digging tooth comprising a body portion having anlend with sharply convergent upper and lower surfaces and slightly conver ent lateral surfaces, and ay removable ho ow oint adapted to be engaged over said end an having internal surfaces arranged and disposed .to engage against the respective convergent sur-faces on said end to provide a wedge engagement therebetween, the upper and lower surfaces of the end of the body ortion having keyways tapering in width w ich engage keys on said point.

3. A digging tooth comprising a body portion having an end with sharply convergent upper and lower surfaces and slightly convergent lateral surfaces, and a removable hollow point adapted to be engaged over said end and having internal surfaces arranged and disposed to engage against the respective convergent surfaces on said end to provide a wedge engagement therebetween, the upper and lower surfaces of the end of the body r portion having keyways tapering in widt which engage keys on said point, the taper of said keys and keyways being opposite to thatof said lateral surfaces.

4. A digging tooth comprising a body portionhaving an end with sharply convergent upper and lower surfaces and slightly/convergent lateral surfaces, and a removable hollow point adapted to be enga ed over internal sur aces arranged and dispose respective convergent surfaces on said end to provide a wedge engagement therebetween,

portion havingekeyways tapering in width which engagel keys on said oint, said keyways being deeper than said eys.

6. A digging tooth comprising a body portion having an end with sharply convergent upper and lower surfaces and slightly convergent lateral surfaces, and a removable hollow point adapted to be engaged over said end 'and having internal surfaces arranged and disposed to engage against the respective Aconvergent surfaces on said end to provide a wedge engagement therebetween, the upper and lower surfaces of the end of the body portion having-keyways tapering in width which engage keys on said point, the taper of said ke -s and keywafvs being opposite to that of sai havinfr a greater depth than said ke s.

7. digging tooth comprising a ody portion having an end with sharply convergent upperand lower 4surfaces vand slightly convergent lateral surfaces, and a removable hollow point adapted to be en aged over said end and having internal sur aces arranged and disposedto engage against the respective convergent surfaces on said end to provide a wedge engagement therebetween the lateral sur aces and lsaid keyways p sisv upper and lower surfaces of the end of the' body portion ,having ke wa s ta erin in width which engagebkeysyonysaid gointgthe taper of said keys and keywa s being opposite and equal to that of said7 lateral surfaces.

Signed by me, this 4th day of October,

LAYTON S. SHAFFER.

to engage against the the upper and lower surfaces ofthe end of tion having an end with sharply convergent upper and lower surfaces and slightly convergent lateral surfaces, and a removable hollow point adapted to be engaged over said end and havingV internal surfacesarranged and disposed to engage against the respective convergent surfaces on said end to provide a wedge engagement therebetween, the upper and lower surfaces of the end of the ,body 

